Chain-stitch sewing-machine.



M. HEMLEB.

CHAIN STITCH SEWING MACHINE.

APPLICATION FILED MAY 16, 1913.

1,123,739, Patented Jan. 5, 1915.

Z SHEETSSHEET 1.

INVENTOR ATTORNEY M. HEMLEB.

CHAIN STITCH SEWING MACHINE.

APPLICATION FILED MAY 1a, 1913.

1,123,739. V Patented Jan. 5, 1915.

2 SHEETS-SHEET 2.

WITNESSES: 30 INVENTOI? a w C 7 2 M W BY ATTORNEY UNITED s ATEs PATENT OFFICE.

MARTIN HEML E B, 0F ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFAC- TUBING COMPANY, A CORPORATION OF NEW JERSEY.

CHAIN-STITCH SEWING-MACHINE.

Specification of Letters Patent.

Application filed Kay 16, 1818. Serial No. 767,875.

To all whom it may concern Be it known that I, MARTIN HEMLEB, a citizen of the United. States, residing at Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Chain-Stitch Sewing-Machines, of which the following is a specification, reference being had therein to the accompanyin drawings.

This invention re ates to an improvement in single thread chain-stitch sewing machines such as that illustrated in patent to Diehl and Houghton, No. 579,223, March 23, 1897, in which a looper-carrying rockshaft beneath the work-plate is operated from a driving shaft journaled in the bracket-arm of the machine, said looper rock-shaft being connected to the driving shaft through a plural-armed rocker.

According to the present invention, the main-shaft .carries separate actuating members .connected respectively with the needlebar journaled in the head of the bracketarm, the reciprocating feed-bar, and the looper rock-shaft mounted beneath the bedplate. The actuating member for the loo er rock-shaft is in the form of a crank, which has a. pitman connection with the lateral arm of a rocker having a second arm which extends u Wardly in the direction of the looper roc -shaft. Said looper rock-shaft likewise carries an arm, which has a short link connection with the upwardly extending arm of said rocker. The link connection is carried between the operating end of said upwardly extending arm and the second rock-shaft to have a short bodily oscillation in its actuation of the looper shaft, and also to swing idly upon the arm of the looper-shaft as an axis to permit dwell of the looper. The construction of the patent above referred to also employs elements similar to those above described, but one arm of the rocker hangs downwardly below, its axis of movement and pivotally supports a relatively long bent link which extends upwardly toward the looper-shaft, being connected to the crank-arm of the latter. In the aforesaid construction the link resists the movement of the rocker when the parts leave their initial position, and the arm of the rocker is compelled to bodily lift the link and carry the same upwardly to advance the looper, and to secure part of its dwell. Inasmuch as the axis of the short depending arm of the rocker is intermediate the ends of the long link, the rocker must be turned approximately 100 to secure the necessary motion and succeeding dwell of the looper-shaft. In the aforesaid construction the high degree of crank eccentricity and the construction and arrangement of the parts prevents speeds beyond 2,400 stitches per minute.

By the present construction, the degree of crank eccentricity, length of throw of the pitman and degree of oscillation of the second rock-shaft are reduced to a minimum the shaft turning approximately 50; and the coacting elements are well balanced and arranged compactly to operate in a path entirely above the second rock-shaft. In the 1n1t1al position of the parts the short link connection is so positioned with respect to the crank-arm of the looper-shaft that its full weight is thrown upon the latter immediately upon the movement of the rockarm, so that the link acts naturally to transmit the looper-advancing motion to the looper-shaft. Indeed, throughout its active and idle movements, the link is maintained above the crank-arm of the looper-shaft; and only for the purpose of retracting the looper-blade from loop-seizing position is the link lifted by the rock-arm. As a result of such construction, the friction and the weight of the bodily moving parts, which has prohibited very high speeds in machines of the present type, is so reduced that the looper mechanism may be operated to exceed thirty five hundred stitches per minute.

In the drawings, Figure 1 is a front side elevation, partly in section, of a sewing machine embodying the improvements, and Fig. 2 a bottom plan of the same. Fig. 3 is a detail view partly in section, of the looper rock-shaft and the elements connecting the same to the driving shaft. Fig. 4 is a transverse section through the bracketarm of a machine embodying the improvements. Fig. 5 is a front view of the elements connecting the looper rock-shaft with the driving shaft. Fig. 6 is an end view Patented Jan. 5, 1915.

of the looper-bar showing the position of a a looper immediately prior to the descent of the needle.

The frame of the machine consists of bedplate 1 to which is secured hollow standard 2 with tubular overhanging arm 3 in the head 4 of which is journaled the reciprocating needle-bar 5 carrying the multiple needle-clamp 6 in whichare secured the eyepointed needles 7. Mounted within and ongitudinally of the bracket-arm is mainshaft 8 having upon its forward end crankplate 9 carrying a crank-pin embraced by one end of the pitman 10 whose opposite end is connected with the collar 11 fixed upon the needle-bar 5. The main-shaft has upon its rearward portion an eccentric 12 which serves to actuate link-bar 13 connected to the usual feed rock-shaft 14, the linkbar 13 being fulcrumed intermediate its ends upon the upper end of a swinging link 15 whose lower end is pivotally mounted upon a depending arm 16 of the usual feedregulating lever mounted upon fixed fulcrum 17 and having a lateral arm 18 by means of which the fulcrum of link-bar 13 is adjusted to regulate the feed.

The main-shaft is provided with looperactuating crank 19 embraced by the strap of pitman-rod 20 whose apertured lower end embraces a stud 21 carried by the lateral arm 22 of a plural-armed rock-shaft 23 having its hub portion journaled upon pins 24 embraced by the endwise-adjustable split bushings 24 mounted in depending lugs 25 and 25 of the bed-plate. Said rock-shaft 23 is provided with an upwardly extending arm 26 which is carried slightly above the axis of looper rock-shaft 27. Said looper rock-shaft 27 is journaled at one end in the inner depending lug 25" and at the other end in depending lug 28 of the bed-plate, the said rock-shaft extending beyond lug 28 and being formed with a socket in which is .secured by means of set-screws 29 the hub of looper-bar 30, said hub at its outer end being mounted within a bushing carried by depending lug 31 of the bed-plate. The looper rock-shaft 27 carries at its rearward end an arm 32, said arm being provided with a collar, which fits upon the looper rock-shaft and is secured against movement thereon by set-screw 33. The upwardly extending arm 26 of rock-shaft 23 is connected to arm 32 of looper rock-shaft 27 by a short link 34, the connections between the link and each arm being pivotal.

In Figs. 1, 2,3 and 5 of the drawings, the

arts are shown in the positions they assume immediately prior to the descent of the me dle-bar, the pitman-rod 20 being in its upper position, and looper-bar 30 holding the loopers in the position shown in Fig. 6 of the drawings. When main-shaft 8 is rotated in the direction of the arrow, Fig. 1, needle-bar 5 and pitman 20 simultaneously descend. In its movement the pitman first carries downward the lower arm 22 of rockshaft 23, thus moving arm 26 in a direction toward said pitman, and swinging link 34 upon its pivotal connection with looper-arm 32 from the position shown in Figs. 3 and 5 to a position in a vertical line drawn through the axis of said pivotal connection, all of. which movement is accomplished without appreciable change in the position of the looper-bar. During the movement thus described, the needles have descended to a position immediately above the work plate. As the pitman completes its downward movement, continuing to swing arm 26 toward it, the movement of link 34 causes rock-shaft arm 32 to move upwardly, thus turning looper rock shaft 27 and causing the loopers to recede from the needles, the needles meanwhile having passed through the loops held by said loopers. The receding movement of the loopers casts off the loops held thereby upon the needles, at which point the parts assume the positions shown in Fig. 4 of the drawings, the pitman being in its extreme lower position. As main-shaft 8 continues to rotate, the action of crank 19 causes pitman 20 to rise, and the preceding movement of looper rock-shaft 27 is reversed by the change in position of the rock-shaft arms and connecting link. By such movement the loopers are advanced toward the needles, and seize the loops held thereon, simultaneously with the rise of the needle-bar, as will be understood without further explanation.

It will be seen that the necessary throw of pitman 20 has. been reduced to a minimum, enabling the use of a crank of slight eccentricity to the main-shaft; and that the range of movement of rock-shaft 23 and link 34 is correspondingly reduced. Such construction so eliminates friction that a higher speed may be given the operating parts than with any former construction of this type. Although former high s eed sewing machines of this type are unab e to work satisfactorily at a speed hi her than 2,400 stitches per minute, a mac ine constructed in accordance with the present invention will 0 erate freely and satisfactorily at a spec exceeding 3,500 stitches per minute, the increase in efiiciency being nearly fifty per cent.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, the combination with the frame, comprising an overhanging bracket-arm, a main-shaft journaled in the bracket-arm, and a reciprocating needlebar, of a looper-actuating pitman connected with said main-shaft, a 100 er rock-shaft, a second rock-shaft connecte to said pitman, an arm carried by said second rock-shaft, an arm carried by said looper rock-shaft, and a short pivotal connection between said arms, said arms and pivotal connection having a path of movement entirely above said second rock-shaft.

2. In a sewing machine, the combination with the frame, comprising an overhanging bracket-arm, a main-shaft journaled in the bracket-arm, and a reciprocating needlebar, of a looper-actuating pitman connected with the main-shaft, a looper rock-shaft, a second rock-shaft connected to the pitman, an upwardly extending arm carried by said second rock-shaft, the operating end of said arm being adapted to oscillate in a short path above said looper rock-shaft, and a pivotal connection between the latter and the operating end of said arm.

3. In a sewing machine, the combination with the frame, comprising an overhanging bracket-arm, a main-shaft journaled in the bracket-arm, and a reciprocating needlebar, of a looper-actuating pitman connected with said main-shaft, a looper rock-shaft, a second rock-shaft connected to said pitman, an upwardly extending arm carried by said second rock-shaft, an arm carried by said looper rock-shaft, and a short link pivotally connecting said arms and carried between the operating end of said upwardly extending arm and said second rock-shaft to have a short bodily oscillation with the axis of said looper rock-shaft asa center.

4. In a sewing machine, the combination with the frame, comprising an overhanging bracket-arm, a main-shaft journaled in the bracket-arm, and a reciprocating needlebar, of a looper-actuating pitman connected with said main-shaft, a 100 or rock-shaft, a. second rock-shaft connecte to said itman, an upwardly extending arm carried by said second rock-shaft, an arm carried by the looper rock-shaft, and a link pivotally connecting said arms, said link being shorter than the upwardly extending arm.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

MARTIN HEMLEB.

Witnesses:

H. A. KOBNEMANN, Jr., WM. P. STEWART. 

